The present invention relates to the general field of image acquisition sensors and controlling such sensors.
More precisely, the invention relates to an image acquisition device enabling a dental radiological image to be obtained, the device comprising a matrix sensor and a control module for the sensor. The invention relates to devices in which the matrix sensor comprises a plurality of image acquisition photodiodes that are sensitive to radiation, together with at least one detection photodiode that is likewise sensitive to radiation.
Such sensors exist, in particular made using complementary metal oxide-on-silicon (CMOS) technology, that make it easy to integrate photodiodes having different geometrical characteristics on a common substrate. It is useful for the detection photodiode(s) to present, for example, a size that is different from the size of the acquisition photodiodes so as to obtain higher sensitivity, enabling radiation to be detected more quickly.
The device of the invention further comprises a control module for controlling the matrix sensor, and arranged to read the detection photodiode periodically and to cause the sensor to change over between at least two modes: a standby mode in which the acquisition photodiodes are inhibited; and an acquisition mode in which the energy received by the acquisition photodiodes is used for acquiring an image.
The term “inhibit” is used to mean that any photons received are not loaded, either by periodically purging the acquisition photodiodes, or by blocking photon reception by the acquisition photodiodes.
In known devices, the changeover is triggered as soon as the detection photodiode detects irradiation by a generator. Generally, receiving a predetermined quantity of light means that irradiation has been detected.
Existing devices thus enable image acquisition to be triggered as soon as the photodiode has received a given quantity of energy in the period between two reads of the detection photodiode.
With known devices, image acquisition is generally performed throughout the duration of irradiation or for a predetermined duration independently of the quantity of energy that is actually sent towards the sensor.